Bovine TB and badgers: “This approach has not been tried anywhere else…”

The different approaches of the various administrations in the UK and Ireland to attempting to eradicate bovine tuberculosis [TB] in wild animals, specifically badgers, are worth noting. They are all in response to the EU Directive 64/432/EEC which, as the Welsh adminstration’s website notes, “requires Member States to provide plans showing how they will eradicate bovine TB in cattle.”

…she had tasked her officials to develop an approach that would involve testing live badgers; vaccinating and releasing the test negative badgers; and removing the test positive ones.

She said: “This approach will focus on removing diseased badgers and protecting uninfected ones. This balanced approach would avoid killing healthy badgers and could lead in time to a healthier badger population incapable of transmitting TB to cattle. This is a powerful message which I hope will be welcomed by environmentalists as well as by farmers.”

The Minister advised that the aim of this wildlife intervention research would be to test the effectiveness of this approach on the level of TB in badgers and in cattle in the north. This approach has not been tried anywhere else and may offer an advantage in moving forward as part of a comprehensive approach that addresses all the factors involved in TB spread.

It’s true that it’s an approach that has not been tried anywhere else. But it was one of the options considered by the Welsh administration. And rejected. Here’s why.

158. There is no field trial evidence to suggest that the combined test, vaccinate and cull approach would reduce the number of confirmed herd breakdowns.

159. The modelling of potential outcomes from the combined test vaccinate and cull approach indicated that the size of the remaining badger population, the level of infection remaining in that population and their disturbance (perturbation) could result in an increase in the number of infected badgers and the number of confirmed herd breakdowns.

160. “There is some support though no evidence base for the value of the removal of individual badgers or setts that are infected and by implication may be epidemiologically important. There is currently no trap-side test that allows for the rapid identification of infected badgers, and there is no information on the outcomes of such an approach with respect to perturbation of badger social structures” (Science Review Report, Page 7, Para 13, see Annex 4). [added emphasis]

161. In conclusion, there is no evidence to suggest that this is a suitable or viable approach to deal with a reservoir of infection in badgers in endemic areas such as the IAA [Intensive Action Area]. [added emphasis]

[Ulster Unionist MLA Robin Swann] “Their intention to trap badgers, vaccinating those which are healthy and culling those which infected, does make sense however I was disappointed that the minister was only able to come to Committee with the headline announcement but very little detail to accompany it.” [added emphasis]

He said significant questions remain however, not least on the practicalities of the testing.

“The department’s intention to use an animal side test with real time results is to be especially welcomed, however they have yet to identify what test they will use and how it will be administered. What we don’t want to see is DARD veterinary officers having to spend exorbitant amounts of time waiting for results of a badger which has to remain anesthetised in a cage beside them.

“Senior DARD officials indicated that they may use a Stat-Pack test, however this was only a possibility, and even then I would be concerned that badgers previously caught and vaccinated may potentially appear positive if caught again.” [added emphasis]

154. There are a number of tests for bovine TB in live badgers. Bacteriological culture of samples, gamma interferon and ELISA tests, can take up to three days for results to be available making them unsuitable for use in this context as badgers would either have to be held captive until the results were available or tested, marked and released then recaptured in the future. The Stat-Pak test is the most promising test for use in a combined vaccination and selective cull strategy. The test is relatively simple to perform, although blood sampling would require badgers to be anaesthetised. The test produces results within 20 – 30 minutes, and has a sensitivity (the ability to identify infected badgers) for detection of bovine TB of 49.2% meaning that half of the truly infected badgers would test negative (and therefore be assumed to be uninfected, vaccinated and released). As discussed later the accuracy of the test is insufficient for the purposes of this option.

And as the Irish Government policy document on badgers, available here, notes [20 December 2011]

Despite considerable research in both Ireland and the U.K. no test on live badgers has proven efficacious in reliably detecting TB infected badgers and thus culling remains the only method of control currently available. [added emphasis]

16. The Science Review recognised that “while a bovine TB Eradication Programme should be informed by the science evidence base, the precise measures adopted will be a political judgement based on an evaluation of a range of factors including the interests of the different stakeholders” (Science Review Report, Page 4, Para 17, see Annex 4). [added emphasis]

One of the first questions for the NI Agriculture Minister to answer is, what resources will be dedicated to developing a “trap-side test that allows for the rapid identification of infected badgers”?